1. Field of the Invention
The present invention relates to an electronic component that is used to mount a chip component, such as a multilayer ceramic capacitor, on a circuit board and that includes an interposer.
2. Description of the Related Art
Many chip components, particularly, many compact multilayer ceramic capacitors are currently used in mobile terminals including cellular phones. The multilayer ceramic capacitors are each composed of a rectangular component body that functions as a capacitor and outer electrodes formed at both opposing ends of the component body.
In general, as indicated in Japanese Unexamined Patent Application Publication No. 8-55752, the multilayer ceramic capacitor has heretofore been electrically and physically connected to a circuit board of a mobile terminal by directly placing and holding the outer electrodes on a mounting land on the circuit board and joining the mounting land to the outer electrodes with bond, such as solder.
Mechanical strain may occur in the multilayer ceramic capacitor due to a variation in voltage occurring in an electronic circuit including the multilayer ceramic capacitor. If the strain occurs, the strain is transmitted to the circuit board to cause the circuit board to vibrate. The vibration of the circuit board may cause a vibration sound which a person hears with his/her ears.
In order to resolve the above problems, for example, Japanese Unexamined Patent Application Publication No. 7-111380 and Japanese Unexamined Patent Application Publication No. 2004-134430 describe technologies not to directly mount the multilayer ceramic capacitor on the mounting land. An interposer formed of an insulating substrate is used in each of Japanese Unexamined Patent Application Publication No. 7-111380 and Japanese Unexamined Patent Application Publication No. 2004-134430. When the interposer is used, the multilayer ceramic capacitor is joined to an upper surface electrode of the interposer and a lower surface electrode of the interposer is joined to a mounting electrode of the circuit board. The upper surface electrode is connected to the lower surface electrode via holes that pass through the interposer.
However, in the structure in Japanese Unexamined Patent Application Publication No. 7-111380, after a component substrate is superposed on a supporting substrate and the component substrate is joined to the supporting substrate with bond, a solder mask is formed on only side surfaces of the component substrate to prevent the solder in the mounting on the circuit board from rising to the component substrate. In other words, since the solder in the mounting does not adhere to the outer electrodes on the component substrate although the solder rises to the side surfaces of the supporting substrate, the component substrate is not strongly restrained. As a result, even if the component substrate vibrates, the vibration is inhibited from being transmitted to the circuit board or the like through the supporting substrate. However, it is necessary to form the solder mask only on the side surfaces of the component substrate after the component substrate is joined to the supporting substrate with the bond, so that the manufacturing cost may possibly be increased in this structure.
Japanese Unexamined Patent Application Publication No. 2004-134430 uses a special structure in which the direction in which the lower surface electrode is arranged intersects with the direction in which the upper surface electrode is arranged in the interposer, that is, the direction in which the outer electrodes of the multilayer ceramic capacitor are arranged intersects with the direction in which an electrode for mounting the interposer on the circuit board is arranged. Consequently, the interposer is increased in size and the shapes of the electrodes of the interposer are made complicated, which causes further increases in cost.